Electrical apparatus for computing a check symbol



Jan. 1, 1957 P. J. c. CHENUS 2,776,091 ELECTRICAL APPARATUS FOR COMPUTING A cascx SYMBOL Filed June 14, 1951 5 Shets-Sheet 1 1 i x Z/T/vnvrax. I 5 E4285 To a 05. 20441.5. (LEW, i o I I z M X14 4,.

Jan. 1, 1957 P. J. c. CHENUS ELECTRICAL APPARATUS FOR COMPUTING A cmscx SYMBOL Filed June 14, 1951 5 Sheets-Sheet 3 WWWWWWWW ao 9 mm 2 a mm mm mv mm JJJJ wwwmwwwwww 1957 P. J. c. CHENUS 2,776,091

ELECTRICAL APPARATUS FOR COMPUTING A CHECK SYMBOL 5 Sheets-Sheet 4 Filed June 14 1951 W? M v d.

Jan l, 1957 P. J. c. CHENUS 2,776,091

ELECTRICAL APPARATUS FOR COMPUTING A CHECK SYMBOL Filed June 14, 1951 5 Sheets-Sheet 5 nited States Patent ()7 ELECTRICAL APPARATUS FOR COMPUTING Av CHECK SYMBOL Pierre Jacques Charles Chenus, Paris, France, assignor to.

Compagnie des Machines Paris, France Bull (Societe Anonyme),

The present invention relates to calculating apparatus for effecting combinations in accordance with a given law so that said apparatus indicates at a given instant a certain result by a change in the condition of one of a group of output channels of the apparatus, and the energisation of one of a group of input channels of the apparatus results in a variation of the said change of condition from this output channel to another output channel as a func-v tion of the energised input channel and in accordance with the said law.

More specifically the broad object of the invention is to provide a calculating apparatus adapted to calculate from a number a checking symbol in terms of a base value N, the value of said checking symbol being equal to the difference between the sums of the digits of odd and even denominations of the number or to the complement to N of said difference. The calculating apparatus essentially comprises a digit entering device to successively enter in true value the digits of a number, two result storage devices under control of control means whereby a single storage device is alternately operative at each digit entry, electrical switching members and connections which are of the type of the so-called columnshift arrangement, adapted in such a way that, when a digit is entered, the value of said entered digit is added to or subtracted from the value of the previously stored result according to which storage device was operative before said digit entry.

For a better understanding of the invention and to show how it may be carried into efiect, the same will now be described with reference to the accompanying drawings, in which:

Figure 1 illustrates the principle of one form of the invention,

Figure 2' is a diagram corresponding to Figure 1,

Figures 3-, 4 and 5 are similar diagrams corresponding to other forms of the invention,

Figure 6 is a diagram illustrating one embodiment of a calculating and checking apparatus according toa first embodiment,

Figure 7 is a diagram illustrating a calculating and checking apparatus according to a second embodiment,

Figure 8 shows a detail of Figure 6 illustrated in ditferent form,

Figure 9 shows a third embodiment and checking apparatus.

In accordance with the invention, it is proposed to provide apparatus comprising an assembly of members, preferably all identical and so disposed as to form a regular panel composed of a series of horizontal and vertical rows. Throughout the following description, members of an electrical nature connected by electrical connecting of a calculating means will be considered, but it is to be understood that the invention is not limited to members of this type and that the said members may equally well be of magnetic, optical, hydraulic or other similar form, or of combined form, the connections made also being of corresponding nature. In addition, it is to'be understood that when ref- 2,776,091 Patented Jan. 1, 1957 erence is made to-an arrangement consisting of rows, or forming a panel, it isnot the material position which is to be considered, but the mutual connections of the elements with one another and with the external elements acting thereon.

It will thus be assumed that a panel of members is provided in accordance with the invention as illustrated in Figure 1. One of these members is diagrammatically indicated at 0, while the others are represented by dots for the sake of clarity of the drawing. There are thus n members, the panel being assumed to be square but it would also be possible without departing from the scope of the invention to provide a rectangular panel comprising nXp members, n and p being dillerent. In the left-hand part of the figure there are 11 input channels E0 to En, corresponding respectively to the n horizontal rows and, at the top and bottom respectively, n-terminals or input channels A0 to An and B0 to En. Each member 0 comprises three terminals or connections e, a,-b and has the following property: If it is energised at a and at e it transmits energisation to b. Preferably, if it is energised at b and at e it conversely transmits energisation to a. This second property, however, is not essential and examples of embodiment of the invention will be shown in which it is not utilised. It will first be assumed that this property exists. The said members are readily conceivable and may vary considerably, that is, they may consist of relay controlled contacts, mechanical members or the like. The members 0 are, in accordance with the invention, connected to the terminals or input members E, A and B as indicated by the continuous lines, that is to say, all the members of one horizontal row of the order x may be energised from a common input member Ex,

all the members of one vertical row of the order z may be energised from a common input ,member 'Bz or may transmit such energisation thereto,

andall the members of one oblique row of the order y maybe energised from a common input member Ay or may transmit such energisation thereto. It is to be noted that when a panel is formed of horizontal and vertical rows, various oblique rows are formed ipso facto, such as the two alignments which have been shown by way of example in chain lines extending from 0, provided that they lead, it necessary by way of a deviation, to the input members at the top and bottom, these modifications being utilisable and also forming part of the invention. Starting with the arrangement shown in Figure 1, and assuming to begin with that the numbers 0, 1 n of the difierent inputs correspond with one another, it will be seen that the simple relation:

tion at Bx (chain line extending from A0). Conversely, the Relation 1 is written:

y= that is to say that if energisation is applied to Ex and to Bz an energisation is obtained at Ay. More especially, if z=0, y should be equal to x. Obviously, supplementary inputs such as Ax could be provided, but it is preferable according to the preferred embodiment of the invention, to consider that the terminals A and B form cyclic assemblies of base 12, that is to say that the Relation 1 or 2 is accurate to within it. Thus, by applying an energisation to Ex and to B0, an energisation at An-x will be obtained in the combining panel. Similarly, the extension (in dot-and-dash lines) of the diagonal of the order y issues at By.

It will be seen from the foregoing that a combining panel of the type shown fin ,lFigure 1 may be employed 3 to. effect additions and subtractions. It may therefore be regarded as a calculating. arrangement. As. will be. seen, in order to adapt the said arrangement to a suitable form in accordance with the preferred embodiments of the invention, itis. necessary. to add. theretoat least someof, the following auxiliary. members:

Members for maintaining the. energisat-ion, impartinga momentary memory to the arrangement.

Members for cancelling out the preceding. energisw. tion for introducing. a fresh energisation.

Utilisation members forstoring. or indicating the voltages, appearing at the. output terminals. of the arrange.- ment, or for. transmitting such voltages to a suitable counting. or checking, device.

Members. for setting'the panel prior tothemtroduction of an energi sation.

Membersfor the. total, cancellation of the. panel.

Members; permitting the choosing of one' oi the following methods of operation; repeated additions, re peated; subtractions, or alternate additions and subtractions.

Such an arrangement with these additions may, beemployed to, effect in a. convenient manner. a series of: alternate additions and subtractions of a. series of numbers. As will beseen, when zerohas. been. introduced into-the. apparatusin order to,set it, thefigures.tobeudealt with. will be successively entered by impulses applied to the. terminals, E for, the corresponding orders. and. the result ill h Obtai ed a ny tan .It will. therefore ,be-seen. hat arran ements, of his nature. are,.PaI Y-' for applicat on to, the calculating. arrangements .ofxthe type referred to, in, United States patent, applications of Knut Andreas Knutsen No. 190,507. of. the 157th Octo.-. ber, 1950 a ndNo. 207,555 ofthe 24th. January, 1951,. and l lo, 2 l6,887 of thc'22nd March, 1951, apart from. h r r is t q s- Before proceeding with the description. of the manner in. which the invention is, carried into effect, the possible modifications, of calculating; panels of this nature will. be.

briefly indicated. Figure 1, may be diagrammatically:

us ra e s. how n F u n. which he r wsindicatethe increasing directions, of thedigits-from Aq to A n, Bo to,Bn, and E9 to; En, and the, diagonal. of the ua n i a s e dir c on o the aforesaid obli rows.

It maybenoted, that,if; a, digit "xf is tobe added;t0. a previously constituted result y, a. broken line may be followed in the direction Ay--O B Z (Fig 2-); to obtainthe new resulgz y-l-x, Conversely if a. digit x-- isto... be subtractec l from; a. previously constituted result. "z, a, similar brolgen line may be followed in the, direction Bz :.O,.,--Ay to obtain the newresult ){FZ-r-K- The presentinyention etieetively-providcs.means adapt;

ed to ma isell obtain th t the n ry -n m x in the calculating apparatus results in adding x when a result y is already stored therein, or in subtracting x when. a result. -z-- is already stored therein. The. com tirntation of entering operations results in a. succession of alternate adding and. subtracting. operations.

Results 2 or y may, assume values. ranging. from-.Ofto n 1, n being the base value considered. If it is desired to begin a series of operations with an addition, it is suificient. to first enter. the value Ointhe storage device al loted to.results "-y; ifit. is desired, as the case maybe,

tobegina. series ofoperations with. a subtraction, it is suiiicientv to first enter the value Oin the storage devicealloted'to results "2.

On Fig. 2, the tracing of the brokenline-inthe directionAynOTBz may be represented by the formula:

Z=.)+ (1), The same tracing: inv a converse direction may, be.rep-. es nt v. e r ulaz.

he mb nati may e. d utsd y gla ina e.

or two of the values x, y or z by their complement to the base. value.v n. I

By way of exemplification, Fig. 3 represents a theoretical diagram wherein x is replaced by n-x, the increasing values running from B to A0. The relevant formulas are:

z=y+nx for addition, and:

y=z (nx) that is:

y=z-n+x for subtraction.

In a s m lar. n r, ac d n to F he.- rele formulas are: n-z=y+x that is:

z=ny-x for addition, and:

y=n-zx for-subtraction.

According to Fig. 5, the corresponding formulas are:

n-z=y.-|-nx that is: =x--y for addition, and:

y=nz-(n-x)- that is:

y= z for-subtraction.

It is easily seen (1) that various result values may be obtained simply by giving values complementary to it to the values x, y, or z; (2) the diagram according to Fig. 5 permits'easily to calculate the difierence between any entered digit lower than n and a previous result whatever maybe the category y or z of the latter.

Assume-x1, x2, x3, x4, etc., are the digits successively entered, and zl, 2, 23, y4, are the corresponding results Formulas 3- and 4- allow one to build up the following 40 table, assuming that, at the start, y=0.

according Entereddiglt Results to E017 the. purposes; of the invention, the eventual carryovers are discarded, since only values lower than; n or in e of heir. omp mentsto. n, a i nifican ihn shcut t e re i v a b mp i i l a sumed, inorder to facilitatethereasoning, that; the; digits; mat s! nt qr. d ive e r m. he combinin p nsl. Q mad 0 ndicts. f; h t er T us, he di it. 3. corresponds to E3, A3 and B3. It is clear that; th-is is bya mesa necessar nd that. s pos l o ut us =9 :r nQ. nh ats gdeTb o he. e te s. nd; he-d i s p o ided. h

It i l. us.

the same for the three entries. bem ssih e t -da ses ts fr rm na hic do not follow one another in the natural orderof; succes-. i n-q hei I h re il now described y Way.v of nsznimitat ve xempleawithi ef re o e-5. wh k n mbo qaleulti d v c st b sh d on. h q atum: a end. a n n ihe h o e l. ia ram. H s 5'- Eigurefi. s composed-of-- two figures, 6q; 'and; 6b, which. a t a ly. cpn tl e. S ere t. s be, nder:- stood. hat hs te mi a s n ic tedbv ha n lines. n; i A x. and- B0. o Bx e dsnt salw tt he. sam terminalsofEigure 6a. r fljherewill be seen in Figure 6a movable. contacts Eq 9. Beula -.11.- re e ther. eco d. ca d r adies. r ltssuu contacts closed by means of a keyboard or any other means.

Each contact energises an entry relay R0 to RX while pairs to the recording electromagnets F0 to Fx on the one hand and to the indicating devices (lamps or the like) 0 to X on the other hand. The circuits of the recording electromagnets (which recording is effected by punching or printing record cards or in a like manner) are completed by the closing of the contact CEand the indicating devices may be operated by closing of the contact CL. The unidirectional elements A80 and ABO are also shown in Figure 6a.

In addition, a trigger arrangement is employed to feed the combining panel alternatively through its upper terminals A0 to Ax or through its lower terminals B0 to Bx, so that the symbol may be automatically calculated by successive differences as digits are entered into the arrangement by depressing the keys E0 to Ex. The principle of such a trigger arrangement will be understood more clearly with reference to Figure 8, which shows the essential parts thereof. The said arrangement comprises in symmetrical arrangement transformers TI or TS, the secondary winding of which feeds a relay RMI or RMS through a rectifier Al or AS, which loads a capacitor CI or CS at the terminals of the said relay. MIK is one of the relays M10 to MIX of Figure 6a, while MSK is one of the relays M50 to MSX. I and S are utilisation arrangements, for example signalling arrangements. E is a key. Assuming first that the trigger arrangement is not energised and that a voltage is momentarily applied to 'J by the contact U, MSK is traversed by a current and CSK is closed. An impulse is set up through AI, RMI is energised and CMI opens momentarily, which has no effect at this instant. S therefore remains energised by CSK. If the contact U is opened again and E is momentarily depressed, there are obtained by an analogous process the closing of CIK, an impulse in AS, the momentary opening of CMS and consequently the breaking of MSK. Owing to the latter breaking, there is also an impulse at the secondary winding of TI, but it is of opposite sign to the preceding impulse and is stopped by AI. I then remains energised when E is raised. Each time that the key E is depressed again, U remaining henceforth open, inversion of the conditions of I and S will be obtained. A relay trigger arrangement is thus obtained which could also be employed to form binary impulse-counting chains, the carryovers of which are effected from I through the connection between an assembly of the type shown in Figure 8 and an analogous assembly.

Any other known trigger arrangement may be employed in the place of that just described and may be associated with the combining panel Without departing from the scope of the invention.

In order to determine the symbol for checking a number by eleven with the aid of the arrangement according tothe invention, the following procedure will be adopted According to the aforesaid patent application of the 17th October, 1950 the said symbol is so determined that the sum of the digits of even order of the number to be checked, including the symbol, is equal to the sum of the digits of uneven order, or the ditfiference between these sums is null, or equal to 11, or 22, or another multiple of the checking base. In the example selected, thechecking base is 11 for checking decimal numbers.

For example, consider the number 38420. Its symbol, as defined by the foregoing, is 8. According to the in Y vention, the arrangement may be used in two Ways.

Either it serves to calculate the symbol, then this symbol is delivered at its output terminals; or the number 38420 is accompanied by its symbol already calculated, thus forming an aggregate datum (384208). In the latter case, the calculating arrangement is used to verify the transcription of the number.

The current is set up at the positive and negative terminals in Fig. 6a. When the current has been set up at these terminals, contact CD will be opened to ensure the resetting of the arrangement, and then re-closed. The

storage relay M80 is energized from the positive terminal through contacts CD, CRD and the return to negative terminal is effected through windings PTI and RD.

As will be seen, at the start, the current passing through relay MStl, indicating a zero, also passes through the starting relay RD, which opens its contact CRD. Now, MSt) is then only energized by its holding contact CSO. M80 being energized, the indicating device 0 may be fed through unidirectional element A80, where key CL is closed. The first digit 3 is entered by depressing key E3,

be opened. An impulse in the relay R3 is therefore suf-' ficient for the value 3 to be introduced into the cornbining panel.

The circuit of M13 includes PTS which induces during the energisation of M13 an impulse in the trigger arrangement which temporarily opens CMS and breaks M80. As CMI is closed, M13 remains energised and indicates 3 through A133 (Figure 6b) until the introduction of the following digit, which is 8.

The closing of E8 energises R8 which closes all the contacts of its horizontal row. B3 is connected to A5 by the contact 85. The positive voltage thus applied energises M and, through TI, energises the relay RMI which breaks CMI and de-energises M13.

At each digit entry, the automatic operation of the trigger device ensures the alternate setting into activity of the upper storage device (MStl-MSX) and lower storage device (Mitt-MIX). In course of the sequential introduction of the digits of the number 38,420, the operation of the apparatus may be summarized by the succession of the result relays at the registering condition, namely: M13; M85; MIX; M53; M18.

If it is desired to calculate the still unknown checking digit corresponding to said number, the operator closes the key CL and sees that this digit is an 8, as being manifested by the operativeness of the indicator device 8, in parallel with relay M18, through terminal B8 and unidirectional element ABS.

If, on the other hand, it is desired to verify the cor-.

respondence of the checking digit with its associated number, after many eventual transcriptions on accounting documents, the succession of operations normally goes on with the final introduction of the read digit 8. As terminal B3 is under voltage as soon as relay MIS is energized, it follows the energization of storage relay MSO, which manifests, through the resetting of the upper storage device, the searched correspondence. An error in the digits of the number or in the checking digit would cause the energization of a storage relay other than M80, among MSl-MSX, which would attract the operators attention when he closes the key CL.

The apparatus may be included in or connected to a printing accounting machine. (Fig. 6a), electromagnet EB may, for instance, serve to control the printing mechanism and cause it to print, on the document under check, a distinctive mark indi- Upon closure of key CC 7 cating that no error was found during the checking process.

The Figure 7 shows a second embodiment of the invention in accordance with the diagram of Fig. 2 and established on the base value 10. It may be noted here that a checking digit or symbol calculated on base 10, nearly provides as good a security against errors as when calculated on base 11, on the condition that it also results from alternate additions and subtractions of the digits of the number handled.

The circuit Fig. 7 is substantially equivalent to that one shown by Fig. 6.1, within the number of relays. Another relay trigger system is shown. The trigger essentially comprises electro-magnet RBl, relay I and cam controlled contact 74, the latter being provided to alternately set under voltage holding lines 708 and 701. Such an alternation is effected at each energization of electro-magnet RBI.

In the conductors forming the connections of the relay contacts controlled by the entry relays R-R9, there always is an incremental direction, that is from top left to bottom right. With respect -to this direction, the digit ent'ry relays R0-R9 are arranged in a normal order, as also are the storage relays MSO-MS9 and MIO-MI9.

The terminals A0-A9 and B0-B9 (Fig. 7) are respectively connected to the terminals with corresponding numbers All-A9 and 130-139 represented on Fig. 6b. This arrangement constitutes an application of the theoretical diagram of Fig. 2.

By way of example, the operation of the apparatus will be described, in relation to an illustrative number, namely, 73561.

It is assumed that, before setting the apparatus under voltage, cam 75 and relay contacts Ia are in the positions shown by the drawing. Upon closure of key CD, relay I becomes energized, thereby transferring its contacts In and applying a positive voltage on holding line 703. The subsequent closure of key contact D causes the energ'ization of relay M50, which holds itself energized through line 708 and its holding contact.

The first digit 7 is then introduced by the closing of contact E7. This causes the energization of relay R7 and eletcromagnet RBI. A circuit is completed from terminal A0, through one of the contacts controlled by R7, to terminal B7 and relay coil M17. Upon energization of RBI the pawl it controls is actuated and turns in a clockwise direction the ratchet wheel integral with cam 75, by a quarter of one revolution, thereby opening contact 74. Relay 1 being deenergized, contact 1a returns to the rest position. It is to be noted that the movable blade of contact In must be of such a size and form that the positive voltage be not removed from line 703 before line 701 is itself set under voltage. M80 is thus de-energized while M17 becomes energized and is held through its holding contact and line 701. When contact E7 is released, RB1 obviously is de-energized and a spring moves back the pawl Without changing the angular position of cam 75.

The introduction 'of the second digit 5 again causes the operation of the relay trigger which transfers contact Ia, thereby permitting the de-ener'gization of relay M17 and the held energization of relay M52.

The whole operation may be summarized by the storage relays successively energized, namely: MI7, M82, M18, and M87. 7

When the operator closes the key-contact C-L (Fig. 6b) the indicator lamp '7 will be lighted, manifesting the value of the resulting symbol. that is 7 which is the difference between the digits of odd denominations (7-|-6=l3) and even denominations (5-}1=6).

According to another example, say the three-digit numher 273, the operation of the arrangement according to Fig. 7 may be summarized by the succession of the storage relays sequentially energized, that is: M12; MSS; and M18.

- When-the operator closes the key-contact CL, the final energization of relay M18 is accompanied by the lighting of indicator lamp 8-. With respect to the difference between'the sums of the digits of odd and even denominations, that is, +27+3=2, the symbol 8 manifested is the complement to 10 of said difference, taking no account of the signs minus or plus.

Another embodiment of the invention will now be described with reference to Fig. 9. This embodiment is designed to give the same results as those given by the circuits shown by Figs. 6a6b and constitute also 'an application of the theoretical diagram of Fig. 5. In a manner similar to Fig. 6a, the values of the entry relays R0RX and storage relays MIX-M10 are allotted to said relays in orders contrary to the incremental order resulting from the vertical and oblique connections. The base value is 11 and there is only one result storage device. A common relay G controls the setting under 'voltage of one holding line and of one control line 101, by means of three contacts G1, G2, G3, two of which (G1 and G3) being contacts with delayed actuation. The delay applies to closing as also to opening, and the delay of contact G1 is greater than that of contact G3.

Each storage relay controls a holding contact, C0 for instance, and one delayed contact C0d, for instance. Push-button Dcontrols the initial entry of 0 in the calculating apparatus. EO-EX are push-buttons, each of which has one normally closed contact and one normally opened contact, to control the entry of the digits to be entered. Thanks to a spring action, all push-buttons return to normal position when released. Output terminals A0-AX are to be connected to the indicating organs shown by Fig. 6b, in accordance with corresponding values.

The operation is as follows. Let the symbol corresponding to the number 63 be calculated. The apparatus is set under voltage by closing key CD. Relay G becomes energized by a circuit extending from positive terminal through key contact CD, wire 103a, relay coil G, Wire 104, the closed contacts E0-EX in series, wires 102e, 1020, 102a, to negative terminal. The momentary actuation of D completes two circuits. The first one extends froin positive terminal I, through key contact CD, wire 103a, relay coil R0, wire 105, upper contact D, wires 1020!, 102c, 102a, to negative terminal thereby closing the horizontal row of contacts controlled by R0. The second one, through lower contact D, sets under voltage the wires a, 110b, 1100. It follows the energization of the storage relay M10, which holds itself energized through C0 and line 100. When push-button D is released, R0 is de-energized but terminal A0 remains under voltage, thanks to contact C0d closed.

The first digit 6 is entered by depressing push-button E6, thereby breaking the energization circuit for relay G, and completing a circuit for relay R6, which closes its horizontal row of contacts. Contact G2 is immediately opened but contact G3 reclose's a little later. During-the time when contact G3 is not yet r'e-closed, line 100 is no longer under voltage and relay M10 is de-energized. Due to the fact that the delay of G1 is greater than the delay of G3, terminal A0 remains under voltage a little time after re-closure of contact G3, permitting, during this time, the completion of a circuit extending from terminal through key contact CD, wires 103a,

a 10312, contact G1 still closed, line 101, contact C0d still closed, wires 110b, 1100, terminal A0, fifth contact from the left controlled by R6, terminal B6, relay coil M16, wires 102b, 102a, to terminal energizing s'aidrelay. As soon as contact G1 is opened, said circuit is broken, but relay M16 holds itself energized through its contact C6 -and line 100.

When push-button E6 is released, relay R6 is dc-east gized and relay G is energized again. As contact G3 is opened a little after contact G2 is closed, the holding circuit for relay M16 is not broken. Still a little after, terminal A6 is set under voltage through G1 closed, line 101, contact C6d closed and wire 116.

Thereafter, the second digit 3 is entered, by depressing push-button E3. Relay R3 closes its contacts and relay G is de-energized. During the time when contact G3 is re-closed and contact G1 is not yet opened, the following circuit is completed: terminal key contact CD, wires 133a, 103b, contact G1 still closed, line 101, contact cs4 still closed, wire U16, terminal A6, wire 106, third contact from the left controlled by R3, terminal B8, relay coil M155, wires 102b, H5261, to negative terminal After breaking of this circuit, relay M18 remains energized, and when E3 is released, terminal A8 remains under voltage, through wire 118 and contact C803.

The indicating device 8 is now operative to display the symbol 8 corresponding to the number 63. As a matter of fact, in the aggregate datum 63 (8), 6-|-83'=ll, which is in accordance with the required condition.

From the foregoing, it is readily seen that the last arrangement performs the operation: zi=riz, wherein Xi is the actually entered digit and z the previous result. In fact the operation rather is effected in form of: Zi=Xi+IZZ, wherein 11:11. When, according tothe p ding example, 3 is entered after 6, xt=3, z=6,-

llz= and the operation is: 3+5: 8, giving the correct result.

It is recalled that the examples hereinbefore described are not intended in any way to limit the scope of the invention and that it is possible in addition to combine the features thereof in order to obtain a varied range of arrangements according to the invention.

I claim:

1. Electrical calculating apparatus for calculating from a number expressed in a numeration system of radix n a checking symbol in terms of a base value N and equal to the difference between the sum of the digits of the odd denominations and the sum of the digits of the even denominations of said number, or to the complement to N of said difference, comprising a digit entering device including a number n of entering relays, each assigned to introduce a distinct digit in the apparatus when operated, energizing means for selectively operating one of said entering relays, a first symbol storage device and a second symbol storage device comprising each a number N of storage relays, each relay either of said storage devices being assigned to one symbol value from 0 to N-l, control means made operative to control the successive operation of said first and second storage device alternately at each digit introduction in the apparatus, a circuit arrangement arranged as an addition table comprising a matrix of two-point make contacts with N columns and 22 rows, the contacts of each row being controlled by an associated one of said entering relays so that the contacts of one row are closed with a digit being introduced into the apparatus, a first group of conductors, a second group of conductors, each conductor of the first group connecting a distinct storage relay of the first storage device to contact points of all the rows, passing to a contact point of a different column for each difierent row, each conductor of the second group connecting a distinct storage relay of the second storage device to other contact points of a single column of said matrix so that with the first storage device operative and an entering relay operated to introduce a new digit, the latter is added without carry over to the value stored in said first storage device and the result is stored in said second storage device, and with the second storage device operative and an entering relay operated to introduce a new digit, the latter is subtracted without carry over from the value stored in said second storage device and the result is stored in said first storage device.

2. Electrical calculating apparatus as claimed in claim 1, wherein each of said storage relays has individual holding means, and including two holding lines each associated with one of said storage devices, and switching means to set into activity at the start of operation a holding means for maintaining its energization, and including two holding lines each associated with one of said storage devices, and switching means to set into activity at the start of operationsa storage relay assigned to the 0 symbol in said first storage device, said control means cooperating with said digit entering device, and

controlling said holding lines so that whenever one of said entering relays is made operative, a storage relay of one of said storage devices is selected for energization through a conductor of each of said groups before the previously energized storage relay in the otherof said storage devices is de-energized.

4. Electrical calculating apparatus for calculating from a number expressed in a numeration system of radix n a checking symbol in terms of a base value N and equal to the difference between the sums of the digits of odd and even denominations of said number, or to the complement to N of said difierence, comprising a digit entering device including N entering relays, each assigned to introduce a distinct digit in the apparatus when operated. energizing means for selectively operating one of said entering relays, a first symbol storage device and a second symbol storage device, each comprising a number N of storage relays, each relay in either of said storage devices being assigned to one symbol value from 0 to N1 and being fitted with individual holding means, two holding lines each associated with one of said storage devices, first switching means for making alive either of said holding lines, a circuit arrangement arranged as an addition table including a matrix of make contacts distributed in N columns and N contact rows, the contacts of each row being controlled by an associated one of said entering relays, so that the contacts of a different row will be closed according to which digit is being introduced in the apparatus, a first group of diagonal conductors in which group each conductor connects contacts pertaining to all the rows but to different columns of the matrix to a separate storage relay in said first storage device, a second group of conductors in which group each conductor connects the contacts of a single column to a separate storage relay in said second storage device, second switching means for energizing one storage relay of 0 value at the start of operation, control means for controlling said first switching means, said first and second storage devices cooperating with said control means so that each time an entering relay is energized, one storage relay in one storage device will be selected for energization through one conductor in both said groups in dependance on which storage relay was previously held energized in the other storage device and on which row of contacts is being closed.

5. Electrical calculating apparatus for calculating from a number expressed in a numeration system of radix n a checking symbol in terms of a base value N and equal to the difierence between the sums of the digits of odd and even denominations of said number, or to the complement to N of said difference, comprising a digit entering device including N entering relays, each assigned to introduce a distinct digit in the apparatus when operated, energizing means for selectively operating one of said entering relays, a first symbol storage device and a second symbol storage device, each comprising a number N of storage relays, each relay in either of said storage devices being assigned to one symbol 11 value from 0 -to N-l and being fitted with individual holding means, two holding lines each associated with one of said storage devices, first switching means for making alive either of said holding lines, a circuit arrangement arranged as an addition table including 'a matrix of makecontacts distributed in N columns and N contact rows, the contacts of each row being controlled by an associated one of said entering relays, so that the contacts of a different row will be closed according to which digit is being introduced in the apparatus, a first group of diagonal conductors in which group each conductor connects contacts pertaining to all the rows but to difierentlcolumns of the matrix to a separate storage relay in said first storage device, a second group of conductors in which group each conductor connects the contacts of a single column to a separate storage relay in said second storage device, second switching means for energizing one storage relay of 0 value at the start of operation, control means for controlling said first switching means, said digit entering device cooperating with said control means so that each time an entering relay is energised, one storage relay in one storage device will be selected for euergization through one conductor in both said groups in dependance on which 12 storage relay was previously held energized in the other storage device and on which row of contacts is being closed.

References Cited in the file of this patent UNITED STATES PATENTS 2,244,700 Horton June 10, 1941 2,364,540 Luhn Dec. 5, 1944 2,404,250 Rajchman July 16, 1946 2,428,811 Rajchman Oct. 14, 1947 2,434,499 Lang Jan. 13, 1948 2,436,178 Rajchman Feb. 17, 1948 2,486,809 Stibitz Nov. 1, 1949 2,502,360 Williams "2.. Mar. 28, 1950 2,538,636 Williams Jan. 16, 1951 2,565,511 McWhirter Aug. 28, 1951 FOREIGN PATENTS 614,639 Great Britain Dec. 20, 1948 650,685 Great Britain Feb. 28, 1951 OTHER REFERENCES Proceedings of the IRE, by Burks, vol. 35, No. 8, August 1947, pages 756 through 767; 12 pp. 

